The two tackled this bold question: What is the cheapest, fastest way to cool the
Earth?

The question assumes, of course, that human activity is a primary cause of long-term
warming; the Earth has warmed over the past 100 years, though it has cooled
recently.

The point: Supposing the Earth got so hot that the doomsday scenarios some are
selling were to come true, what could we do about it?

Levitt and Dubner's research led them to a group of inventors in Bellevue, Wash., at
a company called Intellectual Ventures (IV).

The IV guys are no kooks.

IV was founded in 2000 by Nathan Myhrvold, formerly chief technology officer of
Microsoft. The company has raised $5 billion to invent all kinds of cool solutions,
such as clean, cheap forms of energy.

The IV guys suspect human activity has contributed to warming  we humans have been
burning lots of fossil fuels for a few hundred years now.

They also think that global-warming rhetoric in the media and political circles is
oversimplified and exaggerated.

They think the current generation of climate-prediction models is "enormously crude"
 that there is an enormous amount of natural phenomena the models can't account
for, such as water vapor, the biggest greenhouse gas.

They think the conventional wisdom on how to resolve any potential problems is:

Too little: Conservation efforts, such as wind power, won't cut it.

Too late: Even if we stopped emitting carbon dioxide today, the carbon we've
already emitted will stay in the atmosphere for 100 years.

Too optimistic: It is way too hopeful to believe humans will seriously cut
carbon emissions, as our friends in China demonstrate on a daily basis.

So, supposing human activity were to lead to cataclysm, what could we do?

We could mimic the effects of a giant volcano!

When Mt. Pinatubo erupted in the Philippines in 1991, it pumped millions of tons of
sulfur dioxide into the stratosphere, the area seven miles above the Earth's
surface.

The sulfur dioxide absorbed water vapor and formed an aerosol cloud that rapidly
blanketed the globe. The hazy blanket partially reflected the sun, causing the Earth
to cool.

Thus, IV has proposed a contraption  a giant garden hose, of sorts  that could
be lifted high into the air with helium balloons. It could pump sulfur dioxide
directly into the stratosphere.

It sounds like something from the Willy Wonka chocolate factory, but it would likely
work.

And it would be cheap  a total cost of $250 million. That's less than the U.S.
government spends every hour.

Levitt and Dubner have been assailed by some for oversimplifying a complex matter,
when all they were trying to do was answer a simple question:

What is the cheapest, fastest way to cool the Earth?

In any event, while some prophesy gloom and doom  that the Earth will erupt into a
fiery ball unless we spend trillions to drastically cut greenhouse gas emissions 
I place my hope in human invention and ingenuity.